What Is OPS+ in Baseball? OPS Plus Explained

OPS+ in baseball is on-base plus slugging, adjusted for the hitter’s ballpark and league, and rescaled so that 100 is exactly average. That single move fixes the biggest weakness of raw OPS: a .900 OPS does not mean the same thing in a hitter-friendly bandbox as it does in a cavernous pitcher’s park during a low-scoring year. OPS+ levels those differences, which is why it is the number to reach for when you want to compare hitters across stadiums and eras.

The scale is the whole appeal. You do not have to memorize what counts as a good OPS in a given season — 100 is always average, and everything is a percentage above or below it.

The formula

Baseball Reference builds OPS+ from a hitter’s on-base and slugging rates measured against the league:

OPS+ = 100 × (OBP ÷ lgOBP + SLG ÷ lgSLG − 1)

Here lgOBP and lgSLG are the league averages, and a park factor is applied to account for the hitter’s home stadium. The ”− 1” and the ”× 100” are what center the scale on 100. A result of 130 means the hitter was 30 percent better than league average once park and league are handled.

Note that this is not simply raw OPS divided by league OPS. OBP and SLG are each compared to the league separately before being combined, which is a small but real difference from the shorthand people sometimes assume.

A worked example

Suppose the league averages for a season are a .320 OBP and a .400 SLG. A hitter posts a .400 OBP and a .550 SLG.

• OBP ratio: .400 ÷ .320 = 1.25
• SLG ratio: .550 ÷ .400 = 1.375
• Sum minus one: 1.25 + 1.375 − 1 = 1.625
• OPS+: 1.625 × 100 = 163

So this hitter was about 63 percent better than league average — a genuine MVP-caliber offensive season. (A park adjustment would nudge that final number up or down depending on the home stadium, which is the piece raw OPS never captures.)

How to read OPS+

Because 100 is fixed as average, the tiers are easy to hold in your head.

OPS+	Rating
160 and up	MVP-level, historic
140 to 159	Excellent, All-Star
115 to 139	Very good regular
100 to 114	Above average
90 to 99	Slightly below average
Below 90	Below average

A hitter at 100 is dead average. At 130 they are one of the better bats in the league; at 160 they are in the MVP conversation. The all-time single-season peaks have reached the 250s and 260s — more than 150 percent above the league — which reads almost like a different sport when set against a league of 100s.

Why OPS+ matters, and where it falls short

The value of OPS+ is context. It answers “how good was this hitter relative to their time and place,” which raw OPS cannot. That makes it the honest way to argue whether a 1960s star out-hit a modern one, since it already corrects for the run environment each played in.

It is not flawless. OPS+ inherits OPS’s core simplification — it adds on-base and slugging as if they were equally valuable, when getting on base is worth a touch more. Stats built on linear weights, like wRC+, value each event more precisely and are generally sharper. OPS+ trades a little accuracy for simplicity and wide availability.

If you want the unadjusted starting point, read our explainer on what OPS means, and the two components on their own: OBP and slugging percentage. For the all-in valuation that folds hitting together with defense and baserunning, see WAR in baseball. And to picture the elite end of the slugging half, the most home runs in a season shows the hitters who drove OPS+ into record territory.

Short version: OPS+ is park- and league-adjusted OPS on a scale where 100 is average, 130 is very good, and 160-plus is MVP-level — the fair way to compare bats across parks and eras.